如果我在一段时间后发送缓冲区，我的客户端将正确地发送到服务器。但是，如果我在没有间隔的情况下发送消息，服务器会收到一个缓冲区。例如，如果我发送两个缓冲区“message1”和“message2”，并在这两个发送操作之间放置 1 秒 sleep ，服务器会收到 2 个缓冲区并打印 message1“\n”message2。但是，如果我在没有 sleep 的情况下发送这 2 个缓冲区，服务器将获得 1 个缓冲区并打印 message1message2。我不明白为什么会这样。我的服务器和客户端代码如下。

服务器.c

            #include<stdio.h>
            #include<string.h>    //strlen
            #include<stdlib.h>    //strlen
            #include<sys/socket.h>
            #include<arpa/inet.h> //inet_addr
            #include<unistd.h>    //write

            #include<pthread.h> //for threading , link with lpthread

            void *connection_handler(void *);

            int main(int argc, char *argv[])
            {
                int socket_desc, new_socket, c, *new_sock;
                struct sockaddr_in server, client;
                char *message;

                //Create socket
                socket_desc = socket(AF_INET, SOCK_STREAM, 0);
                if (socket_desc == -1)
                {
                    printf("Could not create socket");
                }

                //Prepare the sockaddr_in structure
                server.sin_family = AF_INET;
                server.sin_addr.s_addr = INADDR_ANY;
                server.sin_port = htons(10240);

                //Bind
                if (bind(socket_desc, (struct sockaddr *)&server, sizeof(server)) < 0)
                {
                    puts("bind failed");
                    return 1;
                }
                puts("bind done");

                //Listen
                listen(socket_desc, 3);

                //Accept and incoming connection
                puts("Waiting for incoming connections...");
                c = sizeof(struct sockaddr_in);
                while ((new_socket = accept(socket_desc, (struct sockaddr *)&client, (socklen_t*)&c)))
                {
                    puts("Connection accepted");

                    //Reply to the client
            //      message = "Hello Client , I have received your connection. And now I will assign a handler for you\n";
            //      write(new_socket, message, strlen(message));

                    pthread_t sniffer_thread;
                    new_sock = malloc(1);
                    *new_sock = new_socket;

                    if (pthread_create(&sniffer_thread, NULL, connection_handler, (void*)new_sock) < 0)
                    {
                        perror("could not create thread");
                        return 1;
                    }

                    //Now join the thread , so that we dont terminate before the thread
                    //pthread_join( sniffer_thread , NULL);
                    puts("Handler assigned");
                }

                if (new_socket<0)
                {
                    perror("accept failed");
                    return 1;
                }
                while (1);
                return 0;
            }



            void *connection_handler(void *socket_desc)
            {
                //Get the socket descriptor
                int sock = *(int*)socket_desc;
                int read_size;
                char *message, client_message[2000];

                //Send some messages to the client
            //  message = "Greetings! I am your connection handler\n";
            //  write(sock, message, strlen(message));
            // 
            //  message = "Now type something and i shall repeat what you type \n";
            //  write(sock, message, strlen(message));

                //Receive a message from client
                while ((read_size = recv(sock, client_message, 2000, 0)) > 0)
                {
                    puts(client_message);
                    //Send the message back to client
                    //write(sock, client_message, strlen(client_message));
                    memset(client_message, 0, sizeof(client_message));
                }

                if (read_size == 0)
                {
                    puts("Client disconnected");
                    fflush(stdout);
                }
                else if (read_size == -1)
                {
                    perror("recv failed");
                }

                //Free the socket pointer
                free(socket_desc);

                return 0;
            }

客户端.c

            #include<stdio.h>
            #include<string.h>    //strlen
            #include<sys/socket.h>
            #include<arpa/inet.h> //inet_addr

            int main(int argc, char *argv[])
            {
                int socket_desc;
                struct sockaddr_in server;
                char *message, server_reply[2000];

                //Create socket
                socket_desc = socket(AF_INET, SOCK_STREAM, 0);
                if (socket_desc == -1)
                {
                    printf("Could not create socket");
                }

                server.sin_addr.s_addr = inet_addr("192.168.246.26");
                server.sin_family = AF_INET;
                server.sin_port = htons(10240);

                //Connect to remote server
                if (connect(socket_desc, (struct sockaddr *)&server, sizeof(server)) < 0)
                {
                    puts("connect error");
                    return 1;
                }

                puts("Connected\n");

                //Send some data
                message = "nayan";
                if (send(socket_desc, message, strlen(message), 0) < 0)
                {
                    puts("Send failed");
                    return 1;
                }
                /*sleep(1);*/
                message = NULL;
                message = "Mazhar vai";

                if (send(socket_desc, message, strlen(message), 0) < 0)
                {
                    puts("Send failed");
                    return 1;
                }
                /*sleep(1);*/
                message = NULL;
                message = "Sarwar vai";

                if (send(socket_desc, message, strlen(message), 0) < 0)
                {
                    puts("Send failed");
                    return 1;
                }
                /*sleep(1);*/
                message = NULL;
                message = "joy";

                if (send(socket_desc, message, strlen(message), 0) < 0)
                {
                    puts("Send failed");
                    return 1;
                }
                /*sleep(1);*/
                message = NULL;
                message = "sumon";

                if (send(socket_desc, message, strlen(message), 0) < 0)
                {
                    puts("Send failed");
                    return 1;
                }
                /*sleep(1);*/
                message = NULL;
                message = "rahim";

                if (send(socket_desc, message, strlen(message), 0) < 0)
                {
                    puts("Send failed");
                    return 1;
                }
                /*sleep(1);*/
                message = NULL;
                message = "karim";

                if (send(socket_desc, message, strlen(message), 0) < 0)
                {
                    puts("Send failed");
                    return 1;
                }

                /*sleep(1);*/
                message = NULL;
                message = "jamal";

                if (send(socket_desc, message, strlen(message), 0) < 0)
                {
                    puts("Send failed");
                    return 1;
                }
                /*sleep(1);*/
                message = NULL;
                message = "kamal";

                if (send(socket_desc, message, strlen(message), 0) < 0)
                {
                    puts("Send failed");
                    return 1;
                }
                /*sleep(1);*/ 
                message = NULL;
                message = "salam";

                if (send(socket_desc, message, strlen(message), 0) < 0)
                {
                    puts("Send failed");
                    return 1;
                }
                //Receive a reply from the server
            //  if (recv(socket_desc, server_reply, 2000, 0) < 0)
            //  {
            //      puts("recv failed");
            //  }
            //  puts("Reply received\n");
            //  puts(server_reply);

                return 0;
            }

最佳答案

TCP 是一种流 协议(protocol)(如使用SOCK_STREAM 所示)。这意味着没有数据包的开始或结束，它只是一个字节流。这也意味着单个接收调用读取的内容可能少于使用单个传输调用发送的内容，或者使用多个(包括尾随的部分)传输调用发送的内容。

要处理它，您需要在 TCP 之上提出一个更高级别的协议(protocol)。它要么需要包含正在发送的数据的长度(以固定长度格式)，要么您需要有一些其他方法来知道消息的开头或至少是结尾。

关于c - 如果客户端发送多个缓冲区而没有休眠，为什么 tcp 服务器会收到一个缓冲区？，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/41676614/